Cyclopentenyl compounds



United States Patent 3,288,862 CYCLOPENTENYL COMPOUNDS RostyslawDowbenko, Gibsonia, Pa., assignor to Pittsburgh Plate Glass Company,Pittsburgh, Pa., a corporation of Pennsylvania No Drawing. Filed Mar.17, 1965, Ser. No. 440,5 3 Claims. (Cl. 260-611) This case is acontinuation-in-part of application Serial No. 49,828, filed August 16,1960 and now abandoned.

This invention relates to cyclopentenyl compounds containing a sidechain of the Formula RO-CH wherein R is hydrocarbon or substitutedhydrocarbon, and to methods of preparing the same. The invention hasparticular relationship to those cyclopentenyl compounds containing theforegoing group in the -position of the cyclopentene ring and asubstituent for hydrogen in the 3-position of said ring.

This invention comprises the discovery that a conjugated cyclic diene;namely, cyclopentadiene of the forwherein R is an alkyl or alkenyl groupcontaining up to 12 carbon atoms.

In the resultant compounds of the structure:

Cami

the halogen X and the olefinic bond are relatively labile and aresusceptible of various reactions to provide a wide variety of usefulcompounds containing a five-member ring, many of which are novelchemical compounds. In order to conduct the reaction to form said 5-alkoxymethyl-3-halocyclopentenes, ethers containing a halomethyl groupupon one side of the oxygen bridge and wherein R is represented by awide variety of groups, including alkyl groups, such as methyl, ethyl,propyl, isopropyl, butyl, isobutyl, amyl, and alkenyl groups such asallyl, methallyl, crotyl and the like, can be employed.

Group X preferably is chlorine, which is the most common halogen, butmay also be bromine, iodine or fluorine. By reason of their lability,the halogens X in the 5-alkoXy-methyl-3-halocyclopentenes may be easilyremoved, it being readily possible to replace them by various groups.The following are representative examples of such groups:

(A) Ester groups having the Formula 3,288,852 Patented Nov. 29, 1966 (asin phthalic acid), CH CH COOH (as in succinic acid), CH=CHCOOH (as inmaleic or fumaric acid) COOH (as in itaconic acid);

(B) Hydroxyl groups (OH); (C) Ether groups, for example and others;

(D) Hydrocarbon groups, such as etc. When the moieties are ofdicarboxylic acids, one or both carboxyls maybe esterified.

The alkoxymethyl halogenated cyclopentenes and the derivatives thereofmay be subject to various reactions, such as hydrolysis, hydrogenations,oxidations, saponifications, dehydrations and Grignard reactions, invarious sequences in order to provide compounds useful per se, or toprovide intermediates in the synthesis of many other compounds.

Thus, the 5-alkoxymethyl-3-halocyclopentenes may be subjected tohydrolysis to replace the 3-halogen by a hydroxyl OH group. The latterproduct can also be obtained by saponification of the corresponding5-alkoxymethyl-3-cyclopentene acetate.

Hydrogenation of the double bond in the cyclopentene ring before orafter the compounds (5-alkoXymethyl-3- cyclopentenylacetate or5-alkoXymethyl-3-halocyclopentene) have been saponified, may behydrogenated to provide alkoxymethylcyclopentanols of the formula:

ROOHZ JOH wherein R is of the significance previously indicated.

Oxidation of certain of these materials can also form ketones, asrepresented by the compound:

The benzylidene substituted derivatives thereof, as represented by3-ethoxymethyl 2,5-dibenzylidenecyclopentanone of the formula:

CH CHzO 011 is methyl, phenyl, benzyl, or the like.

It will be recognized that cyclopentadienes in the foregoing reactionsmay often be replaced by substituted cyclopentadienes, such as methyl orethyl-substituted cyclopentadiene, wherein 1, 2 or 3 ring hydrogens arereplaced by methyl, ethyl or like substituents. Thealkoxymethyl-3halocyclopentenes obtained by reacting a cyclopentadienewith hemiacetal halides may be represented by the formula:

ROC- X R, R R and X have the significance previously given, and R R Rand R may be hydrogen or saturated hydrocarbon groups containing from 1to about 4 carbon atoms and being represented, for example, by methyl,ethyl, propyl or other alkyl groups.

The compounds herein disclosed may be used for various purposes. Some ofthem may be used in the preparation of perfumes, drugs, insectrepellants, etc. Those containing olefinic or conjugated diolefinicbonds may be polymerized as by addition reactions to give homopolymerresins which can be spread as protective and/or decorative films uponwood and metals. They may also be copolymerized under heat and pressure,or in the presence of Friedel-Crafts catalysts, with monomers such asstyrene, or with glyceride drying oils such as linseed oil.

Some of the useful methods and products contemplated herein areillustrated by the following examples.

Example I This example is typical of the preparation of aS-alkoxymethyl-3chlorocyclopentene.

In the reaction, halornethyl ethers of the formula ROCH X (R and Xhaving the significance previously described) are prepared by the usualmethods. A convenient method is to react paraformaldehyde with anappropriate alcohol to supply the group R, in the presence of a hydrogenhalide, e.g., hydrogen chloride.

In a typical example, 1 mole of methyl chloromethyl ether was dissolvedin a solvent, e.g., 100 milliliters of ether. This solvent may also bereplaced by a like volume of petroleum pentane, carbon tetrachloride, orother solvent or solvent mixture which is nonreactive. The reaction maybe smoothly and efliciently catalyzed with a small amount of a catalyst,e.g., 2 milliliters of a solution containing 5 grams of a Friedel-Craftscatalyst, such as stannic chloride, in 100 milliliters of carbontetrachloride or other solvent.

To the methyl chloromethyl ether solution were added 1.1 moles ofcyclopentadiene in 100 milliliters of the solvent used for thechloromethyl ether component.

' pentadiene.

Addition was slow (in the experimental batch, being over a period ofabout 1 hour and being dropwise) and the mixture was cooled to atemperature of about 0 C. to about 3 C. The reaction mixture, after allingredients were in, was stirred at the same temperature for about 1.5to 2.5 hours, after which 0.5 milliliter of triethylamine was added.

The solvent was evaporated at room temperature, but under vacuum toobtain the desired 5-methoxymethyl-3- chlorocyclopentene in a formsuitable for use in many of the reactions herein disclosed.

The material was purified by distillation in the presence of a fewpellets of potassium hydroxide. The distillate under a vacuum of 0.3millimeter of mercury, boiled at a temperature in the range of 40 C. to50 C. The pressures herein given in each instance are absolute. Therefractive index (11 of the distillate was 1.4672.

The techniques of the foregoing reaction were repeated with thefollowing chloromethyl ethers:

1 Methyl chloromethyl ether. 2 Ethyl chloromethyl ether. 3 Isopropylchloromethyl ether. 4 Butyl chloromethyl ether. 5 Allyl chloromethylether.

to provide the compounds of the following table:

TABLE A No.: Name of Compound 1 5 methoxymethyl 3 chlorocyclopentene. 25 ethoxymethyl 3 chlorocyclopentene. 3 5 isopropoxymethyl 3chlorocyclopentene. 4 5 butoxyniethyl 3 chlorocyclopentene. 5 5allyloxymethyl 3 chlorocyclopentene.

The procedure as outlined in the foregoing example is typical. It willbe evident that substantial variations in reaction conditions may oftenbe used; thus, atmospheric, superatmospheric or subatmospheric pressuresmay be used in reacting the halomethyl ether with the cyclo Thetemperatures of reaction also are susceptible of variation, for example,in a range between 30" C. and 25 C., or such other temperatures as willpermit the desired reaction to proceed at a reasonable speed withoutundue volatilization of the reactants. The tin salt may be replaced byvarious Friedel-Crafts type catalysts and if speed of reaction is notimportant, the catalyst may be omitted entirely from the reactionmixture.

Relative proportions of the halomethyl ether and cyclopentadiene may bevaried. Naturally, the two materials actually react in equivalentamounts, and an approximation of such ratio is usually preferred; butfor special purposes, halomethyl ether may be used in a ratio varying,for example, from about 0.25 to about 6 moles per mole ofcyclopentadiene. The ingredient used in preponderant amount acts as adiluent and may be recovered by distillation or by solvent extraction orother methods at the end of the reaction.

Example II In this example, 5-alkoxymethyl-3chlofocyclopentenes preparedby the method of Example I were reacted with sodium acetate in thepresence of acetic acid to form esters ofS-alkoxymethyl-3hydroxycyclopentene.

In a specific reaction, 4 moles of sodium acetate were dissolved in 1200milliliters of acetic acid and the solution cooled to 60 C., and thecrude S-ethoxymethyl-Iichlorocyclopentene prepared from 2 moles ofcyclopentadiene using the method of Example I, was slowly added.

The mixture was heated at C. for 20 to 24 hours;

A 34.5-gram fraction of impure 4-.ethoxymethyl-2-cyclopentenyl ether,boiling at about 105 C. at a presusre of 0.2 millimeter of mercury andgiving a refractive index (11 of 1.416 was also obtained. The formula of4- product was primarily -ethoxymethyl-3-cyclopentenyl 5ethoxy-methyl-2-cyclopentenyl ether is:

acetate.

This reaction was repeated using the various compounds of Table A as thealkoxymethyl-3-chlorocyclopentenes.

The properties of the several acetate products are as An 884-gram sampleof crude 5-ethoxymethyl-3-chlofollows: rocyclopentene from reaction of 5moles of cyclopenta- Analyses Boiling Point Pressure Index of N0. (TableA) Refraction 2 Formula Theory Found 1 C. Mm. Hg 0 H O H 4.5 1.451909111103... 63.51 8.29 63.8664.06 8.498.60 4. 1. 4491 C10H15O3 65.198.76 65 1165. 29 8.608.64 2.75 1. 4463 C1iH1sOs. 66. 64 9.15 66 3366 418. 999. 02 6 0 1.4493 C!2H2003 67.89 9. 50 68. 0368. 19 9. 539. 42 35 1. 4601 CUI'IIGOL. 67.32 8.22 66-72-6679 8. 00s. 07

2 Measured at 23 0., 23 C., 23 0., 24 C. and (3., respectively.

Example III In this example, the conversion of a S-alkoxy-methyl-3-chlorocyclopentene to the corresponding 5alkoxymethyl-3-hydrocyclopentene is illustrated.

In the reaction, 320 grams (3 moles) of sodium carbonate were dissolvedin 2 liters of water and 553 grams of crude5-ethoxymethyl-3-chlorocyclopentene prepared from 3 moles ofcyclopentadiene by the techniques of Example I, were added. The reactionwas mildly exothermic and the temperature rose to 32 C. and remained sofor 45 minutes. The mixture was then heated to about 75 C. for about 4.5hours to insure completion of the reaction. A shorter or longer reactiontime could be utilized and higher or lower temperatures could also beused. When it was evident that reaction was complete or substantiallycomplete, the reaction mixture was cooled and extracted with ether.

Fractional distillation gave 223 grams (52 percent of theory) of liquid,boiling in a range of 72 to 85 C. at a pressure of 3 millimeters ofmercury. The refractive index (n was 1.4639. This product by infraredanalysis gave a strong absorption band at 2.98 microns, indicating thepresence of hydroxyls, and another at 9 microns, indicating the etherlinkage.

The material was fractionally distilled and a fraction boiling at 90 C.under a pressure of 5 millimeters of mercury was considered to beessentially S-ethoxymethyl- 3-hydroxycyclopentene, which is of thetheoretical formula Theoretical and experimentally determined analyseswere as follows:

Experimental Analyses Theoretical Analysis Sample 1 Sample 2 C H C H C Hdicne by the techniques of Example I, were hydrolyzed with 690 grams (5moles) of potassium carbonate in 2 liters of Water, using the techniquessubstantially as described for sodium carbonate. Distillation gave alowboiling forefraction which was primarily unreacted 5-ethoxymethyl-3-chlorocyclopentene, followed by 321 grams of a yellowliquid boiling between 71 C. at 5 millimeters of mercury and C. at 3millimeters of mercury, and a further 190-gram fraction of yellow liquidboiling between 87 C. at a pressure of 0.6 millimeter of mercury.

By fractional distillation, portions boiling in a range of 83 C. to C.at 4 to 5 millimeters of mercury were obtained from the 321-gramfraction. The refractive indices ranged between 1.4632 and 1.4650.

The product contained 5ethoxymethyl-3-hydroxycyclopentene. The otheralkoXymethyl-3-halocyclopentenes may be converted to the 3-hydroxycompounds in similar manner.

Example IV In this example, 3-(ethoxymethyl)cyclopentanol of the wasobtained by the hydrogenation of 5-ethoxymethyl-3- hydroxycyclopenteneprepared for 5-ethoxymethyl-3- chlorocyclopentene as described inExample III. The ethoxymethyl group could be replaced by otheralkoxymethyl groups as herein disclosed.

In the hydrogenation reaction, 28.4 grams (0.20 mole) of5-ethoxymethyl-3-hydroxycyclopentene, boiling in a range of 72 C. to 82C. at 2.5 millimeters of mercury and having a refractive index (11 of1.4639- was dissolved in milliliters of methanol; 1 milliliter of Raneynickel was added as a hydrogenation catalyst and the mixture was placedin a hydrogenation apparatus. The theoretical amount of hydrogen wastaken up in about 15 minutes.

A theoretical yield (28.8 grams) of a colorless oil boiling in a rangeof 83 C. to 93 C. at a pressure of 4.5 millimeters of mercury wasdistilled. The refractive index (n was 1.4507. Infrared analysis gave astrong band at 2.97 microns, showing that the product was primarily analcohol, 3-ethoxymethylcyclopentanol, having the empirical formula C H OTwo samples were analyzed and checked very well with the theoreticalanalysis.

In this example, the acetate of a 3-alkoxymethylcyclopentenyl alcoholwas obtained by hydrogenation of the corresponding acetate of5-alkoxymethyl-3-hydroxycyclopentene.

In the reaction, 36.8 grams (0.2 mole) of the acetate of5-ethoxymethyl-3-hydroxycyclopentene, boiling in a range of 89 C. to 92C. at 4 millimeters of mercury, was dissolved in 150 milliliters ofethyl acetate and l milliliter of Raney nickel was added as ahydrogenation catalyst.

The mixture was shaken with hydrogen in a hydrogenation apparatus at apressure of about 50 p.s.i. for about 2.5 hours, at which time thepressure drop was equivalent to an uptake of 103 percent of thetheoretical amount of hydrogen. Filtration and distillation of thefiltrate yielded 36 grams of colorless liquid boiling in a range of 76C. to 78 C. under a pressure of 0.8 millimeter of mercury. A middlefraction boiling at 77 C. at 0.8 millimeter of mercury had a refractiveindex (11 of 1.4393. The formula was assumed to be C H O whichcorresponds to 3-(ethoxymethyl)cyclopentyl acetate. Two samples wereanalyzed and the theoretical and experimental analyses are as follows:

The product was essentially 3-(ethoxymethyl)cyclopentyl acetate.

Example VI In this example, 3-(ethoxymethyl)cyclopentyl acetate issubjected to saponification with an alkali to provide3-(ethoxymethyl)cyclopentyl alcohol.

In the reaction, a mixture of 27 grams (0.145 mole) of acetate of3-(ethoxymethyl) cyclopentyl alcohol, boiling at 76 C. to 78 C. at apressure of 0.8 millimeter of mercury, and 22 grams of potassiumhydroxide were dissolved in a mixture of 150 milliliters of methanol and20 milliliters of water. The mixture was refluxed for 4 hours and mostof the solvent was distilled oil under vacuum.

The residue was poured into water and was extracted with ether. Theextract gave, upon distillation, 13 grams of a liquid which wasredistilled to obtain 11 grams of a colorless liquid boiling in a rangeof 90 C. to 94 C. at a pressure of 6 millimeters of mercury.

The refractive index (11 was 1.4535. A strong infrared band, indicatinga hydroxyl group, was obtained at 2.97 microns. There was no bandindicating carbonyl groups. The formula C H O corresponding to3-(ethoxymethyl)cyclopentyl alcohol, was assumed and was closelyconfirmed by analysis of duplicate samples.

ANALYSES Experimental Theoretical Sample 1 Sample 2 C H C H C H ExampleVII In this example, 3-(ethoxymethyl)cyclopentanone was prepared from3-(ethoxymethyl)cyclopentyl alcohol by oxidation of the latter withchromic acid.

In the reaction, 3-(ethoxymethyl)cyclopentyl alcohol, boiling in a rangeof 88 C. at a pressure of 5.5 millimeters of mercury to 95 C. at 4.5millimeters of mercury, was used as a starting material.

The charge comprised 10 grams (0.07 mole) of the alcohol dissolved in 30milliliters of acetic acid.

To this solution was added dropwise over a period of 75 minutes, asolution of 5 grams (0.050 mole) of chromic acid dissolved in 5milliliters of water and 15 milliliters of acetic acid. The temperatureof the mixture remained in a range of 30 C. to 40 C. during theaddition. After all the chromic acid solution was in, the mixture wasfurther stirred for 1 hour at room temperature, and 3.5 hours at 40 C.

The reaction mixture was then diluted with water, neutralized with solidsodium bicarbonate, and extracted with ether. The extract was washedwith aqueous sodiurn carbonate and dried.

(C 3CH2OCHFUO) as a colorless liquid boiling in a range of C. at apressure of 7 millimeters of mercury, to 89 C. at 9 millimeters ofmercury. The refractive index (11 was 1.4428. The theoreticalcomposition was C H O The theoretical analyses and the actual analysesas conducted upon two samples are compared as follows:

ANALYSES Actual Analyses Theoretical Analysis Sample 1 Sample 2 C H O HC H The 2,4-dinitrophenylhydrazone of the 3-(ethoxymethyl)cyclopentanonemelted at 81 C. to 82 C.

The theoretical analysis of the hydrazone based upon the formula C H N Oand the actual analysis of -duplicate samples are compared as follows:

The solution was cooled and 0.3 gram of sodium methoxide was added as acatalyst. The temperature was then allowed slowly to rise to that of theroom. After a few hours, the mixture crystallized to a yellow solid.More methanol was addedand 6.5 grams of a greenish yellow solidcrystallized and was filtered off, leaving a greenish oil in thefiltrate. The melting point of the solid was 101 C. to 104 C. Afterseveral further crystallizations from methanol, a yellow crystallineproduct having a melting point of 121 C. to 122 C. was separated. Thiswas considered to be 3-ethoxymethyl-2,5- dibenzylidenecyclopentanone,having a structural formuand being of the empirical formula C H O Thetheoretical analysis and the actual analyses in du- In this example, themethacrylate ester of 5-ethoxymethyl-3-hydroxycycl-opentene was formedby reacting 5- ethoxymethyl-3-chlorocyclopentene and sodiummethacrylate. The reaction charge comprised:

S-ethoxymethyl 3 chlorocyclopentene grams 97 Sodium methacrylate a do 54Hydroquinone (polymerization inhibitor) do 1 Dimethylformamide (solvent)"milliliters" 200 The mixture was heated at 100 C. for 20 hours and wasthen cooled, poured into water and extracted with ether. The extract wasthen washed with aqueous sodium bicarbonate and dried of water.

The solvent was evaporated and the residue was distilled to obtain 61grams of yellow liquid boiling in a range of 45 C. to 117 C. at apressure of 0.3 millimeter of mercury.

Fractional distillation produced 33 grams of a colorless liquid boilingin a range of 92 C. to 101 C. and mainly in a range of 98 C. to 100 C.at a pressure of 0.8 millimeter of mercury. The refractive index (n was1.4628. Infrared spectrum examination showed a band at 6.11 microns,indicating unsaturat-ion. Comparison of the theoretical compositionbased upon the formula C H O and the composition based upon actualanalysis is as follows:

ANALYSES Actual Analyses Theoretical Analysis Sample 1 Sample 2 O H C HC H The material contains a vinyl C=CH group in the 3-position; it maybe used to form polymers and interpolymers. The ethoxymethyl group maybe replaced by other alkoxymethyl groups as herein disclosed. Forexample, the alkoxy gnoup maybe prop'oxy, butoxy, allyloxy, ormethallyloxy.

Example X In this example, 5-butoxymethyl-3-methoxycyclopentene wasformed by reacting 5-butoxymethyl-3-chlorocyclopentene with methanol andpotassium hydroxide.

The reaction mixture comprised 42 grams (0.75 mole) of potassiumhydroxide in 750 milliliters of methanol, to which was added the crude 5-butoxymethyl-3-chlorocycl'opentene from a 0.5 mole run ofcyclopentadiene and butoxychloromethane. The temperature of the reactionmixture rose to 42 C. and the mixture was then refluxed for 5 hours.

The reaction mixture was poured into water and extraoted with a mixtureof ether and benzene. The extract solution was evaporated and distilledto obtain 72 grams of a yellow liquid boiling in a range of 55 C. at apressure of 7 millimeters of mercury, to C. at a pressure of 4millimeters of mercury.

The yellow liquid was further fractionated to give 39 grams of acolorless liquid of a boiling point of 91 C. to 92 C. at a pressure of 5millimeters of mercury. The product had the composition C H O which isthe empirical formula of 5-butoxymethyl-3-meth'oxycyclopentene.Duplicate samples of the material were subjected to analysis. Theseanalyses are compared with the theoretical analysis of the compound asfollows:

In this example, 5-eth'oxymethyl-3-phenoxycyclopentene was prepared bythe reaction of 5-ethoxymethyl-3-chl-orocyclopentene and phenol in thepresence of potassium carbonate.

The reaction charge comprised a mixture of 47 grams (0.50 mole) ofphenol, 70.5 grams (0.51 mole) of potassium carbonate, and 300milliliters of acetone. To the mixture was added dropwise over a periodof 1 hour, a solution of 0.50 mole of the crude 5-ethoxymethyl-3-chlorocyclopentene dissolved in 100 milliliters of ether. The resultantmixture was refluxed at 50 C. for 22 hours, was cooled and poured intowater, and was then extracted with ether. The extract was washed withdilute aqueous sodium hydroxide and volatile constituents wereevaporated, leaving a yellow liquid. Fractionation of the liquidproduced a forerun of unreacted chloride, followed by 33.5 grams of acolorless liquid having a boiling range of 118 C. to 132 C. at apressure of 1.2 millimeters of mercury. The refractive index (21 was1.5201. The product had the empirical formula C H O which corresponds tothe composition of -ethoxymethyl-3-phenoxycyclopentene. Duplicatesamples of this material were subjected to quantitative carbon hydrogenanalysis and the values obtained are compared with the theoretical valueas follows:

ANALYSES Experimental Analyses Theoretical Analysis Sample 1 Sample 2 CH O H C H Example XII In this example, ethoxymethylcyclopentane wasformed by the hydrogenation of 5-ethoxymethyl-3-chlorocyclopentene.

In the reaction, 48.3 grams (0.30 mole) ofS-ethoxymethyl-3-chlorocyclopentene having a boiling range of 43 C.under a .pressure of 0.02 millimeter of mercury, to 54 C. under apressure of 0.08 millimeter of mercury and of a refractive index (24 C.)of 1.4667, was used as a primary material. To this material were added35 grams (0.36 mole) of triethylamine, 100 milliliters of ethyl acetateand 7 milliliters of Raney nickel catalyst. The mixture was shaken in ahydrogenation apparatus with hydrogen for 5.5 hours, at the conclusionof which time, 0.58 mole of hydrogen had been taken up.

The reaction mixture was poured into water and extracted with ether, andthe extract phase was successively washed with acetic acid and aqueoussodium bicarbonate, and was then dried. The product was twicefractionally distilled to obtain a forefraction and 15.9 grams (41.5percent of theory of a colorless liquid which apparently wasethoxymethylcyclopentane. This liquid was distilled and a middlefraction of a boiling point of 145 C. to 146 C. was retained foranalysis. The refractive index was 1.4256. The material had an empiricalformula of C H O. Upon the basis of this formulation, the theoreticaland the experimentally determined analyses are compared as follows:

ANALYSES Experimental Analyses Theoretical Analysis Sample 1 Sample 2 CH C H C H Example XIII ride formed by the reaction was filtered off as awhite solid.

The filtrate was thoroughly washed first with dilute acetic acid andthen with aqueous sodium bicarbonate, and was then dried. The solventwas evaporated off to give 93.6 grams of a residue which was distilled,leaving 84 grams of a yellowish liquid boiling in a range between 54 C.at a pressure of 17 millimeters of mercury, and 165 C. at 0.7 millimeterof mercury.

Distillation gave lower boiling fractions, e.g., a fraction boiling in arange between 44 C. at a presure of 4.5 millimeters of mercury, and 48C. at a pressure of 0.3 millimeter of mercury, and a main fraction ofyellowish liquid boiling in a range between 93 C. at a pressure of 1.1millimeters of mercury, and 120 C. at a pressure of 1.5 millimeters ofmercury.

From this liquid was fractioned 35 grams of a colorless liquid boilingin a range of C. to 135 C. at a pressure of 1.5 millimeters of mercury,and having a refrac'- tive index (11 of 1.4928.

The lower boiling fractions reacted with maleic anhydride, forming awhite solid melting in a range of 122 C. to 126 C. This fraction wasrich in the conjugated diene ethoxymethylcyclopentadiene of the formula:

Uomoomom This conjugated diene may be reacted with other monomers and byaddition or by Diels-Alder reaction. The compound in pure or mixed statemay be reacted with linseed oil or other oils containing two or moredouble bonds to give a drying oil capable of drying to form coatings. Itmay thus replace cyclopentadiene in the process of modifying dryingoils, as disclosed in Patent No. 2,689,232 to H. L. Gerhart.

The fraction boiling in the range of 100 C. to 135 C. as abovedescribed, apparently is a dimer with the ring structure ofdi-cyclopentadiene:

I (1113 jtoHiomn wherein R is hydrocarbon, e.g., methyl, ethyl, propyl,allyl, phenyl or benzyl, and n is a number from 1 to 2.

This dimer, when spread as a paint or varnish film, will air dry atatmospheric pressure in 24 hours and can be baked to hard, adherentstate in 1 hour at 100 C.

The material develops very strong bands in the infrared spectrum at 2.9microns and 5.85 microns.

In a further extension of the techniques of this example, triethylaminewas replaced as a dehydrochlorinating agent by trimethylpyridine. Thetemperature selected for reaction was 50 C. The reaction was thencompleted in 8 hours.

Purification resulted in a colorless liquid boiling in a range of 95 C.to 115 C. at a pressure of 0.2 millimeter of mercury, with a refractiveindex (21 of 1.4928, which matched that of the material in thepreparation of which the dehydrochlorination base was triethylamine. Theinfrared spectra of the two materials also matched. The last materialapparently was also a dimer.

A 12.5-gram sample of this dimer, after absorption of 0.061 mole ofhydrogen, gave 10 grams of a material which was a colorless liquidboiling in a range between 75 C. at a pressure of 0.02 millimeter ofmercury and C. at a pressure of 0.05 millimeter of mercury. Therefractive index (21 was 1.4842. The infrared spectrum of this materialdeparted substantially from that of the material before hydrogenation.

Example XIV' In accordance with this example, the halogen, such aschlorine, in t-alkoxymethyl-3-halomethylcyclopentene is solved in etherto provide a 175-rnilliliter solution.

reacted with a Grignard reagent to replace said halogen with ahydrocarbon group. Five-tenths (0.5) gram mole of methyl magnesiumiodide was dissolved in 300 milliliters of ether, and there was addeddrop by drop over a period of 1.5 hours, a cold solution of 0.5 mole ofthe crude -ethoxymethyl-3-chloromethylcyclopentene dis- The resultantreaction was highly exothermic.

The mixture fas refluxed for 45 minutes, during which time an intensegreen coloration developed and a green oil precipitated. The reactionmixture was allowed to stand for 0.5 hour and a saturated, aqueousammonium chloride solution was added to split oft magnesium iodidechloride in well-known manner, and leaveS-ethoxymethyl-3-methylcyclopentene.

The solvent was evaporated and the residue was fractionally distilled toobtain 25 grams of a dark orange liquid boiling in a range of 44 C. at apressure reduced to 11 millimeters of mercury, to 45 C. under a pressureof millimeters of mercury. The liquid was washed with a reducing agent;namely, aqueous sodium sulfite, and was redistilled to obtain 23 gramsof a nearly colorless liquid boiling at 68 C. to 69 C. at a pressure of34 millimeters of mercury, and having a refractive index (11 of 1.4357.The liquid decolorized bromine in carbon tetrachloride and exhibited aninfrared spectrum free of bands showing the presence of hydroxyl andcarbonyl groups.

Duplicate carbon-hydrogen analyses gave values corresponding to theempirical formula C H O. The values obtained are as follows:

ANALYSES Experimental Analyses Theoretical Analysis Sample 1 Sample 2 GH C H C H The product was essentially pure 5-ethoxymethyl-3-methylcyclopentene of the formula:

CHzCHzOCHw-CHg Example XV 5-ethoxymethyl-3-chlorocyclopentene wasreacted with a Grignard reagent; namely, phenylmagnesium bromide.

In the reaction, 0.54 mole of 5-ethoxyme'thyl-3-chlorocyclopentenedissolved in milliliters of benzene was stirred into 1.0 gram mole ofphenylmagnesium bromide over a period of 1.5 hours.

The reaction was exothermic and a solid precipitated at the end of thereaction. The mixture was refluxed for 16 hours and was then cooled.Magnesium bromidechloride was split olf by the addition of an excess ofsaturated aqueous ammonium chloride to provide5-ethoxymethyl-3-phenyl-cyclopentene.

The product was extracted with petroleum pentane, the solution fromwhich was distilled to give 106 grams (96 percent of theory) of ayellowish liquid boiling in a range of 35 C. at a pressure of 0.2millimeter of mercury to C. at a pressure of 0.03 millimeter of mercury.This material was twice fractionated to obtain 82.8 grams (76 percent oftheory) of a colorless liquid boiling in a range of 87 C. to 99 C. at apressure of 0.1 millimeter of mercury. The middle portion boiling in therange of 95 C. to 96 C. at a pressure of 0.1 millimeter of mercury andhaving a refractive index (n of 1.5219 was subjected in duplicate tocarbon-hydrogen analyses. The results and the corresponding theoreticalvalues, based upon the empirical formula C H O for 5-'ethoxymethyl- 3phenylcyclopentene, are tabulated as follows:

1. A 5-(alkenoxymethyl)-3-chlorocyclopentene wherein the alkenyl portionof the alkenoxymethyl group contains 1 to 12 carbon atoms.

2. A compound as in claim 1 wherein the alkenyl group is selected fromthe group consisting of allyl, methallyl, and crotyl.

3. A S-(allyloxymethyl)-3-chlorocyclopentene.

References Cited by the Examiner Straus et al.: Justus LiebigsAnnalender Chemie, vol. 525 (1936), pages 151182 (pages 158 and 159relied on), QD1L7.

LEON ZITVER, Primary Examiner.

B. HELFIN, Assistant Examiner.

1. A 5-(ALKENOXYMETHYL)-3-CHLOROCYCLOPENTENE WHEREIN THE ALKENYL PORTIONOF THE ALKENOXYMETHYL GROUP CONTAINS 1 TO 12 CARBON ATOMS.